<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css3动画</title>
    <style>
        body {
            background: #ccc;
        }
        .box{
            width: 300px;
            height: 120px;
            margin: 100px auto;
            
            border-radius: 10px;
            background: url('paopao.png') no-repeat left top,
                url('paopao.png') no-repeat right bottom;
            background-color: #036;

            transition: all 3s;
        }
        .box:hover {
            background: url('paopao.png') no-repeat right bottom,url('paopao.png') no-repeat left top;
            background-color: #630;
            transform: rotate(90deg);
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>